Carbon

Carbon
Allotropes
• Carbon can bond with itself in at least
three different ways giving us 3 different
materials
– Diamond
– Graphite
– Buckyballs and nanotubes
Diamond
• Carbons are bonded
via sp3 hybridization
to 4 other carbon
atoms forming a giant
network covalent
compound.
Properties of Diamond
• High melting point due to strong directional
covalent bonds (3550 C)
• Extremely hard because it is difficult to break
atoms apart or move them in relation to one
another
• No electrical conductivity because electrons are
localized in specific bonds
• Insoluble in polar and non-polar solvents
because molecular bonds are stronger than any
intermolecular forces
Graphite
• Carbon atoms are
bonded via sp2
hybridization.
• Carbon atoms form
sheets of six sided
rings with p-orbitals
perpendicular from
plane of ring.
Graphite Structure
• Carbon has 4 valence
e- to bond with. 3 are
used for closest
atoms in rings. 1 is
delocalized in porbitals
• The presence of porbitals allows for
strong van der waals
forces that hold the
sheets together
Properties of Graphite
• Different from Diamond
– Conducts electricity because of delocalized
electrons
– Slippery can be used as lubricant, sheets can
easily slip past each other (think of a deck of
cards)
• Same as Diamond
– High melting point (higher actually because of
delocalized e-, 3653C)
– Insoluble (same reason)
Fullerenes
• Buckyballs: spherical
• Nanotubes: tube
shaped
• Both have very
interesting properties
– Super strong
– Conduct electricity and
heat with low
resistance
– Free radical scavenger
Buckyballs
• Carbon atoms bond in
units of 60 atoms (C-60)
forming a structure similar
to a soccerball with
interlocking six sided and
five sided rings.
• sp2 hybridization
• Extra p-orbitals form pi
bonds resulting in
– Electrical conductivity
– Stronger covalent bonds,
therefore stronger
materials